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Questions tagged [power]

The electricity drained by a device

694 questions
141
votes
8 answers

How can I keep my Mac awake AND locked?

I want to leave my Mac awake overnight so it syncs 4GB of data from Dropbox. I need to prevent the machine from going to sleep because that pauses the Dropbox sync I've been using Caffeine to keep the computer awake, but it also keeps the computer…
Tom Lehman
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12 answers

Can I use 45/60/85W MagSafe era MacBook chargers interchangeably?

I have a 13" Macbook Pro that came with a 60W power adapter and a 15" Macbook Pro that came with a 85W power adapter. There seems to be disagreement in the Apple forums. Can I use either adapter with any portable Mac?
AlanKley
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13 answers

How can I avoid my MacBook Pro giving me minor shocks?

The aluminum Macbook Pro gives a mild shock when connected to a wall socket and charging. It only happens when I'm, for example, not wearing shoes or slippers and my feet are resting on the ground (i.e. by body is acting as a conductor). I contacted…
Code Poet
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7 answers

Turning Power Chime Off

On new Macbook Pro, Power Chime runs. Whenever I delete from core services it comes right back. It makes a sound when plugging in your power cord even when the volume is at 0%. The solution I have now to disable this annoying sound is an AppleScript…
user7875084
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61
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5 answers

Use caffeinate to prevent sleep on lid close on battery

The native caffeinate utility is not working to prevent my macbook from sleeping when I close the display. Instead, the system sleeps and various network services ( VPN, screenshares, VOIP calls, messaging clients, file transfers ) to fail while I…
here
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votes
5 answers

Can I tell my Mac to charge to 80% only?

I leave my MacBook plugged in for days at a time, so the battery stays charged to 100%. Despite Apple claims to the contrary*, I believe that the battery's capacity would be better preserved if I could keep it at an 80% state-of-charge. Is there any…
Doug
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55
votes
10 answers

What would happen if I use a power supply with a different wattage than the system is designed for?

My girlfriend has a Macbook Air. The power supply is smaller and lighter than the Pro. It has an output of 14.85V and 3.05Amps. My Pro Retina has a power supply that is 20V and 4.25 Amps. Both supplies have the same Magsafe adapter, so the…
makerofthings7
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5 answers

Is it OK to charge my iPhone with my iPad charger?

I have an iPhone 4 and an iPad. Since the iPad really charges best off the wall charger I keep it plugged in, but I usually just charge the iPhone off the computer. Although frequently if the iPad is charged I will charge the iPhone with the wall…
Jim McKeeth
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29
votes
14 answers

How to retrieve current wattage info on OS X?

Is there a way to retrieve the current watt usage info on OS X Snow Leopard? I'm using mid-2010 iMac, so I'm not looking for just battery-related apps. Does OS X even monitor power usage? Do I need to use an external reader between the power cord…
Jari Keinänen
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27
votes
4 answers

How to monitor USB power consumption?

I'm looking for a way to monitor the power being drawn from the USB ports on my Mac. System Profiler doesn't appear to display this and I haven't been able to find any applications or tools to do the job either. Can anyone suggest anything…
skeevey
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23
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4 answers

Why does GPS on the iPhone use so much power?

I keep reading in articles that GPS on the iPhone, or any cell phone for that matter, uses a lot of power, but I've never heard an explanation of why. Why is this? The phone doesn't have to transmit like it does with 3G or WiFi. Does the actual act…
Charles Shopsin
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20
votes
7 answers

iPad displays "Not Charging" when plugged into USB ports. What can I do?

When I plug my iPad into my computer's USB ports, the iPad battery area displays "Not Charging". I understand the iPad requires more wattage to charge compared to an iPhone or iPod, as evidenced by the iPad's larger power adapter (10W) vs the…
Chris W. Rea
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19
votes
4 answers

How does Apple calculate the energy consumption of a process in OS X Mavericks

In OS X Mavericks you can monitor the energy consumption of different processes in Activity Monitor. Here we can see 'Energy Impact' and Avg Energy Impact' and that the values can exceed 100. Also there will be a menu bar icon which lists the most…
Kilosh
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3 answers

What are the consequences of using a low-wattage USB-C power supply with a MacBook Pro?

This question pertains to USB-C not MagSafe. MagSafe negotiates available power with the Dallas 1-wire protocol. USB Power Delivery (PD) is an unrelated protocol. Answers based on experience with MagSafe are unlikely to be relevant. I'm considering…
Quentin
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18
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4 answers

Force "low power mode" on mac

When there is less than 5% battery left on a mac, the battery indicator goes red and system performance significantly drops - presumably in an attempt to make that remaining 5% last a little longer. Is there a way to manually trigger this, so that…
muzzamo
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